The present invention relates to encapsulated perfume particles, especially for delivery of high impact accord (HIA) perfume ingredients, and detergent compositions comprising these encapsulated perfume particles, especially granular detergents.
Most consumers have come to expect scented detergent products and to expect that fabrics and other items which have been laundered with these products also have a pleasing fragrance. In many parts of the world handwashing is the predominant means of laundering fabrics. When handwashing soiled fabrics the user often comes in contact with the wash solution and is in close proximity to the detergent product used therein. Handwash solutions may also develop an offensive odor upon addition of soiled clothes. Therefore, it is desirable and commercially beneficial to add perfume materials to such products. Perfume additives make laundry compositions more aesthetically pleasing to the consumer, and in some cases the perfume imparts a pleasant fragrance to fabrics treated therewith. However, the amount of perfume carryover from an aqueous laundry bath onto fabrics is often marginal. Industry, therefore, has long searched for an effective perfume delivery system for use in detergent products which provides long-lasting, storage-stable fragrance to the product, as well as fragrance which masks wet solution odor during use and provides fragrance to the laundered items.
Detergent compositions which contain perfume mixed with or sprayed onto the compositions are well known from commercial practice. Because perfumes are made of a combination of volatile compounds, perfume can be continuously emitted from simple solutions and dry mixes to which the perfume has been added. Various techniques have been developed to hinder or delay the release of perfume from compositions so that they will remain aesthetically pleasing for a longer length of time. To date, however, few of the methods deliver significant fabric and wet solution odor benefits after prolonged storage of the product.
Moreover, there has been a continuing search for methods and compositions which will effectively and efficiently deliver perfume into an aqueous laundry bath providing a relatively strong scent in the headspace just above the solution, then from the laundry bath onto fabric surfaces. Various methods of perfume delivery have been developed involving protection of the perfume through the wash cycle, with subsequent release of the perfume onto fabrics.
One method for delivery of perfume in the wash cycle involves combining the perfume with an emulsifier and water- soluble polymer, forming the mixture into particles, and adding them to a laundry composition, as is described in U.S. Pat. No. 4,209,417, Whyte, issued Jun. 24, 1980; U.S. Pat. No. 4,339,356, Whyte, issued Jul. 13, 1982; and U.S. Pat. No. 3,576,760, Gould et al, issued Apr. 27, 1971. However, even with the substantial work done by industry in this area, a need still exists for a simple, more efficient and effective perfume delivery system which can be mixed with laundry compositions to provide initial and lasting perfume benefits to fabrics which have been treated with the laundry product.
Another problem in providing perfumed products is the odor intensity associated with the products, especially high density granular detergent compositions. As the density and concentration of the detergent composition increase, the odor from the perfume components can become undesirably intense. A need therefore exists for a perfume delivery system which substantially releases the perfume odor during use and thereafter from the dry fabric, but which does not provide an overly-intensive odor to the product itself.
By the present invention it has now been discovered that perfume ingredients, can be selected based on specific selection criteria to maximize impact during and/or after the wash process, while minimizing the amount of ingredients needed in total to achieve a consumer noticeable benefit. Such compositions are desirable not only for their consumer noticeable benefits (e.g., odor aesthetics), but also for their potentially reduced cost through efficient use of lesser amounts of ingredients.
The present invention solves the long-standing need for a simple, effective, storage-stable delivery system which provides surprising odor benefits (especially wet solution odor benefits) during and after the laundering process. Further, encapsulated perfume-containing compositions have reduced product odor during storage of the composition.
The present invention relates to modified starch encapsulated High Impact Accord (xe2x80x9cHIAxe2x80x9d) perfume particles; said particles comprising a modified starch and HIA perfume oil comprised of at least two HIA perfume ingredients which have a boiling point at 760 mm Hg, of 275xc2x0 C. or lower, a calculated CLogP of 2.0 or higher, and an odor detection threshold less than or equal to 50 parts per billion (ppb), wherein the perfume ingredients are encapsulated with the modified starch.
The present invention further relates to laundry compositions comprising from about 0.01% to 50% (preferably from about 0.05% to 8.0%; more preferably from about 0.05% to 3.0% and most preferably from about 0.05 to 1.0%) of a perfume particle according to the present invention and in total from about 50% to about 99.99% preferably from about 92% to 99.95%; more preferably from about 97% to 99.95% and most preferably from about 99% to 99.95%) of conventional laundry ingredients selected from the group consisting of surfactants, builders, bleaching agents, enzymes, soil release polymers, dye transfer inhibitors, fillers and mixtures thereof.
All percentages, ratios, and proportions herein are on a weight basis unless otherwise indicated. All documents cited are hereby incorporated by reference in their entirety.
The present invention provides perfumed, dry particulate detergent compositions useful for the washing of fabrics having an especially desirable and noticeable odor attributable to a modified starch encapsulated HIA perfume particle. The HIA perfume oil contains at least two HIA perfume ingredients. An HIA perfume ingredient has a boiling point at 760 mm Hg, of 275xc2x0 C. or lower, a calculated log10 of its octanol/water partition coefficient, P, of about 2 or higher and an odor detection threshold less than or equal to 50 ppb.
The HIA perfume ingredients are selected according to specific selection criteria described in detail hereinafter. The selection criteria further allow the formulator to take advantage of interactions between these agents when incorporated into the modified starch encapsulate to maximize consumer noticeable benefits while minimizing the quantities of ingredients utilized.
It is also preferable to use both free perfume and encapsulated perfume in the same particulate detergent composition, with the two perfumes being either the same, or two different perfumes. Normally, the free perfume provides the product (or container) perfume fragrance, and covers any base product odor, while the encapsulated perfume provides the in-use perfume odor when the detergent composition is diluted into the wash water.
HIA Perfume Oil
The HIA perfume oil comprises HIA perfume ingredients. An HIA perfume ingredient is characterized by its boiling point (B.P.), its octanol/water partition coefficient (P) and its odor detection threshold (xe2x80x9cODTxe2x80x9d). The octanol/water partition coefficient of a perfume ingredient is the ratio between its equilibrium concentrations in octanol and in water. An HIA perfume ingredient of this invention has a B.P., determined at the normal, standard pressure of about 760 mm Hg, of about 275xc2x0 C. or lower, an octanol/water partition coefficient P of about 2,000 or higher, and an ODT of less than or equal to 50 parts per billion (ppb). Since the partition coefficients of the preferred perfume ingredients of this invention have high values, they are more conveniently given in the form of their logarithm to the base 10, logP. Thus the preferred perfume ingredients of this invention have logP of about 2 and higher.
The boiling points of many perfume ingredients, at standard 760 mm Hg are given in, e.g., xe2x80x9cPerfume and Flavor Chemicals (Aroma Chemicals),xe2x80x9d Steffen Arctander, published by the author, 1969, incorporated herein by reference.
The logP values of many perfume ingredients have been reported; for example, the Pomona92 database, available from Daylight Chemical Information Systems, Inc. (Daylight CIS), Irvine, Calif., contains many, along with citations to the original literature. However, the logP values are most conveniently calculated by the xe2x80x9cCLOGPxe2x80x9d program, also available from Daylight CIS. This program also lists experimental logP values when they are available in the Pomona92 database. The xe2x80x9ccalculated logPxe2x80x9d (ClogP) is determined by the fragment approach of Hansch and Leo (cf., A. Leo, in Comprehensive Medicinal Chemistry, Vol. 4, C. Hansch, P. G. Sammens, J. B. Taylor and C. A. Ramsden, Eds., p. 295, Pergamon Press, 1990, incorporated herein by reference). The fragment approach is based on the chemical structure of each perfume ingredient, and takes into account the numbers and types of atoms, the atom connectivity, and chemical bonding. The ClogP values, which are the most reliable and widely used estimates for this physicochemical property, are preferably used instead of the experimental logP values in the selection of perfume ingredients which are useful in the present invention.
Odor detection thresholds are determined using a gas chromatograph. The gas chromatograph is calibrated to determine the exact volume of material injected by the syringe, the precise split ratio, and the hydrocarbon response using a hydrocarbon standard of known concentration and chain-length distribution. The air flow rate is accurately measured and, assuming the duration of a human inhalation to last 12 seconds, the sampled volume is calculated. Since the precise concentration at the detector at any point in time is known, the mass per volume inhaled is known and hence the concentration of material. To determine whether a material has a threshold below 50 ppb, solutions are delivered to the sniff port at the back-calculated concentration. A panelist sniffs the GC effluent and identifies the retention time when odor is noticed. The average across all panelists determines the threshold of noticeability.
The necessary amount of analyte is injected onto the column to achieve a 50 ppb concentration at the detector. Typical gas chromatograph parameters for determining odor detection thresholds are listed below.
GC: 5890 Series II with FID detector
7673 Autosampler
Column: JandW Scientific DB-1
Length 30 meters ID 0.25 mm film thickness 1 micron
Method:
Split Injection: 17/1 split ratio
Autosampler: 1.13 microliters per injection
Column Flow: 1.10 mL/minute
Air Flow: 345 mL/minute
Inlet Temp. 245xc2x0 C.
Detector Temp. 285xc2x0 C.
Temperature Information
Initial Temperature: 50xc2x0 C.
Rate: 5C/minute
Final Temperature: 280xc2x0 C.
Final Time: 6 minutes
Leading assumptions:
(i) 12 seconds per sniff
(ii) GC air adds to sample dilution
An HIA perfume oil is composed of at least two HIA perfume ingredients, each HIA perfume ingredient having:
(1) a standard B.P. of about 275xc2x0 C. or lower at 760 mm Hg, and;
(2) a ClogP, or an experimental logP, of about 2 or higher, and;
(3) an ODT of less than or equal to 50ppb and greater than 10 ppb,
and is encapsulated in a modified starch as described hereinafter, and used in a particulate detergent cleaning composition. The HiA perfume oil is very effusive and very noticeable when the product is in use as well as on fabric items that come in contact with the wash solution. Of the perfume ingredients in a given perfume oil, at least 40%, preferably at least 50% and most preferably at least 70% are HIA perfume ingredients.
Table 1 gives some non-limiting examples of HIA perfume ingredients.